Análise numérica de estruturas celulares cilíndricas

Abstract

In the oil industry, the decrease of weight of flexible pipelines influences the costs of the entire extraction system. These ducts are usually exposed to high pressures and axial compression, which may cause sudden failures. Therefore, intensive studies are being carried out to find alternatives that enhance the properties of the functional layers that constitute the flexible pipes. An option to the pipes formed by layers of composite materials is to insert, additionally, a cellular tubular metallic reinforcement. Cellular solids enable to choose a geometric shape that can improve a desired mechanical property. Thus, this work studies the mechanical behavior specifically of the cellular cylindrical metallic reinforcement. The objective is to obtain a qualitative analysis comparing seven geometries: hexagonal (θ = 30°, 20° and 40°), reentrant auxetic (θ = -20° and -10°), triangular and square. The structures are subjected to compression loads, for static analysis and linear buckling, and internal pressure. These loads are evaluated independently and, subsequently, in combined modes. For the structural analysis, finite element modeling is performed using the commercial software ABAQUS. The results of the simulations show that the structure with triangular cells is the most rigid in the axial direction and the one which supports the highest load before failing through linear buckling. When compressed, the square cell structure shows, particularly, negligible radial displacement. Although, it presents low resistance to linear buckling. The structures with hexagonal cells result in the lightest weight, the highest radial displacement when compressed and the highest axial displacement when submitted to internal pressure. The reentrant auxetic cells shows the highest axial flexibility and low resistance to buckling. But when exposed to internal pressure, they result in the lowest stress values.